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Initial weaning strategy in mechanically ventilated adults

Initial weaning strategy in mechanically ventilated adults
Literature review current through: Jan 2024.
This topic last updated: Nov 14, 2022.

INTRODUCTION — Liberation from mechanical ventilation is an important process in recovery of critically ill patients in the intensive care unit. It is a three-step process, consisting of readiness testing, weaning, and extubation. Patients who wean successfully have less morbidity and mortality and use fewer resources than patients who require prolonged mechanical ventilation [1-4]. Thus, ensuring that patients wean in a safe and effective way is important for patient outcomes.

The practice of weaning varies widely. Our approach to initial weaning methods is reviewed here. Assessment of a patient's readiness to wean, extubation, and management of the difficult to wean patient are described separately. (See "Weaning from mechanical ventilation: Readiness testing" and "Extubation management in the adult intensive care unit" and "Management of the difficult-to-wean adult patient in the intensive care unit".)

DEFINITIONS

Readiness testing — Readiness testing uses clinical criteria (and occasionally physiological tests) to determine whether a patient is ready to begin weaning from mechanical ventilation (table 1). (See "Weaning from mechanical ventilation: Readiness testing".)

Weaning — Weaning is the process of decreasing the degree of ventilator support and allowing the patient to assume a greater proportion of their own ventilation (eg, spontaneous breathing trials or a gradual reduction in ventilator support). The purpose is to assess the probability that mechanical ventilation can be successfully discontinued. (See "Extubation management in the adult intensive care unit".)

Simple wean – Patients are considered to have undergone a simple wean when they pass their first weaning trial, typically a spontaneous breathing trial (SBT). This is the subject of this topic review.

Difficult-to-wean – Patients are considered difficult-to-wean if they fail their first SBT and then require up to three SBTs or seven days to pass an SBT [5]. This population is discussed separately. (See "Management of the difficult-to-wean adult patient in the intensive care unit".)

Prolonged weaning – Patients are considered to have undergone prolonged weaning if they fail at least three SBTs or require more than seven days to pass an SBT. (See "Management and prognosis of patients requiring prolonged mechanical ventilation".)

Extubation — Extubation is the removal of the endotracheal tube (ETT) and is the final step in liberation from mechanical ventilation support. (See "Extubation management in the adult intensive care unit".)

CHOOSING A WEANING METHOD — For patients who have been intubated for more than 24 hours and have been deemed as ready to wean (see "Weaning from mechanical ventilation: Readiness testing"), we suggest a weaning trial. Patients who are intubated for less than 24 hours do not necessarily need to undergo a weaning trial (eg, patients who undergo short-term intubation for airway protection or minor surgery).

Daily spontaneous breathing trials (SBTs) with inspiratory pressure support is our preferred method of weaning based upon randomized trials that have shown it is efficient, safe, and effective [6-8]. However, practice varies widely. (See 'Daily spontaneous breathing trials (SBTs)' below and 'Variation in practice' below.)

Older methods include progressive decreases in the level of pressure support during pressure support ventilation (PSV) and progressive decreases in the number of ventilator-assisted breaths during intermittent mandatory ventilation (IMV). (See 'Alternative methods' below.)

Newer weaning methods include computer-driven automated PSV weaning and early extubation with immediate use of postextubation noninvasive ventilation (NIV). (See 'Selecting manual or automated weaning' below and 'Extubation to noninvasive ventilation' below.)

Selecting manual or automated weaning — Weaning protocols can be manual (ie, personnel-driven) or automated (ie, computer-driven) [8-16]. There is insufficient evidence to definitively conclude that one method is superior to the other. We generally prefer manual protocols because they can be tailored to the patient, they are less costly, and because most of the available clinical trials that demonstrated efficacy used manual protocols [11,12]. While automated systems are less labor-intensive, there are fewer clinical trial data supporting their efficacy.

Manual protocols – A manual system is one where, following a daily assessment of readiness to wean, healthcare staff manually alter the ventilator settings so that the patient undergoes a weaning trial. Such protocols are usually respiratory therapy- or nursing-driven. While effective, manual protocols are labor-intensive and compliance can be challenging, especially in a busy environment [13,17,18].

Automated systems – Automated systems use proprietary, computerized, closed loop weaning software packages that automate weaning by pressure support. Once the patient is deemed ready for weaning by healthcare staff, the automated weaning program adjusts levels of pressure support during the weaning trial to keep the patient in a normal range of intermittently-monitored respiratory rate, tidal volume, and exhaled carbon dioxide. Once the patient is stable at a specific level of pressure support, the program automatically reduces the pressure support level and reassesses respiratory stability.

Some patients may not be suitable for automated weaning. For example, patients whose baseline arterial carbon dioxide tension (PaCO2) is >60 mmHg should not be weaned by automated systems, since a PaCO2 >60 mmHg is the upper limit of the target range in most weaning software packages. In addition, automated systems are generally not necessary in the postoperative setting when extubation is expected within a short period of time (eg, one to two days) following surgery.

Evidence supporting protocolized weaning – The efficacy of ventilator liberation protocols is supported by numerous clinical trials and meta-analyses comparing protocolized weaning versus no protocol (ie, physician judgment) [11,12]. In a meta-analysis of 14 trials (2205 patients), protocolized weaning reduced mechanical ventilation (MV) duration by 26 percent (95% CI 13 to 37 percent), which corresponds to a reduction of approximately 25 hours (95% CI 12 to 36 hours) assuming an average MV duration of 96 hours without protocolized weaning [12]. Intensive care unit (ICU) length of stay was reduced by 11 percent (95% CI 3 to 19 percent), which corresponds to a reduction of approximately one day (95% CI 0.2 to 1.5 days), assuming an average ICU length of stay of eight days without protocolized weaning. Both groups had similar mortality rates (22 percent each) and reintubation rates (9.4 percent in the protocolized weaning group versus 11.9 percent in the control group). The clinical trials included in the meta-analysis were heterogeneous with regard to the population studied and protocol used. Most protocols were driven by nursing and respiratory therapy staff and included a daily assessment of readiness to wean, followed by a weaning trial if deemed ready. The effect on reducing MV duration did not appear to differ in trials using manual weaning protocols compared with computer-driven approaches; however, only two trials (n=154) used computer-driven protocols, which limits the conclusions that can be drawn from this subgroup analysis. The relative effect size appeared to differ according to type of ICU, with larger effect size in patients admitted to surgical ICUs (47 percent reduction in MV duration [95% CI 20 to 65 percent]), medical ICUs (29 percent reduction [95% CI 7 to 46 percent]), and mixed ICUs (21 percent reduction [95% CI 2 to 36 percent]); and little to no effect in patients admitted to neurointensive care units (1 percent reduction in MV duration [95% CI 20 percent decrease to 18 percent increase]).

Comparison of automated versus manual protocols – Small randomized trials comparing computer-driven automated weaning systems with non-automated weaning have reached variable conclusions [10,19-22]. In a meta-analysis of 7 randomized trials (516 patients), patients managed with computer-driven automated systems had shorter MV duration compared with patients in the control group (mean difference one day; 95% CI 0.09-1.9 days) [23]. Mortality and hospital length of stay were similar in both groups. Two other meta-analyses reported similar findings [19,22]. An important limitation of these meta-analyses is that the control group in many of the trials consisted of "usual care" without a standardized weaning protocol. In the one trial that directly compared automated weaning with a standardized non-computer-driven weaning protocol, MV duration was similar in both groups (10.5 versus 11 days, respectively) [10]. In addition, most trials included in the meta-analyses evaluated one specific proprietary system and the findings may not be generalizable to other systems.

Daily spontaneous breathing trials (SBTs) — For most patients with acute respiratory failure on mechanical ventilation, we suggest an SBT as the initial weaning strategy. In an SBT, the patient breaths spontaneously through the endotracheal tube (ETT) for a set period of time, typically 30 minutes to two hours. The amount of ventilator support used for the SBT and the duration are discussed below. (See 'Choosing ventilatory support' below and 'Trial duration' below.)

Approximately 50 to 75 percent of patients pass the initial SBT and are able to be successfully extubated [7,14,24]. For patients who fail the initial SBT, we suggest ongoing weaning with daily SBTs rather than other weaning strategies such as gradual PSV or IMV weaning. A strategy of extubation with immediate application of NIV may be an option for select patients who fail the initial SBT and are at high risk of having further difficulty weaning and extubating (eg, patients with chronic obstructive pulmonary disease [COPD] or chronic hypercapnic respiratory failure). (See 'Alternative methods' below.)

Evidence supporting daily SBTs — The practice of performing daily SBTs is supported by randomized controlled trials and meta-analyses [7,8,12]:

SBT versus usual care – The available evidence suggests that compared with usual care (ie, weaning at the discretion of the attending physician), performing daily SBTs reduces MV duration. In a meta-analysis of eight trials (1188 patients), protocolized weaning with daily SBTs reduced MV duration by 16 percent (95% CI 0 to 30 percent), which corresponds to a reduction of approximately 15 hours (95% CI 0 to 29 hours) assuming an average MV duration of 96 hours without daily SBTs [12].

SBT versus other weaning strategies – Based on the available evidence, it is unclear if weaning with daily SBTs is superior to other protocolized weaning strategies such as gradual PSV or IMV weaning. The previously described meta-analysis provided an indirect comparison of SBT-based weaning protocols versus gradual PSV or IMV weaning protocols and did not detect a significant difference between the two approaches; both were more effective than usual care with similar effect sizes [12]. Two small randomized trials have directly addressed this question and reached different conclusions. One trial found that patients weaned with daily SBTs (using T-piece (figure 1)) were successfully extubated sooner than patients who underwent gradual PSV or IMV weaning [7]. The second trial found that patients who underwent gradual PSV weaning had a shorter weaning duration and higher likelihood of successful extubation compared with patients who underwent daily T-piece SBTs or gradual synchronized intermittent mandatory ventilation (SIMV) weaning [14].

The conflicting findings of the two trials may be related to differences in how the SBTs were performed in each trial. In the first trial, patients were extubated if they tolerated a two-hour SBT [7]. The patients were unlikely to develop respiratory muscle fatigue because they were closely monitored and returned to full ventilatory support at the first sign of distress. In contrast, in the second trial, clinicians could request up to three separate SBTs over a 24 hour period, each lasting two hours, before deciding whether to extubate a patient [14]. It is possible that these very prolonged SBTs using a T-piece resulted in fatigue, a process that can take 24 or more hours to reverse (figure 2) [25]. In other words, respiratory fatigue may have slowed the progress of patients weaned via SBTs in the second trial.

One reason why IMV weaning may be less successful than SBT or PSV weaning is that the degree of respiratory muscle rest on IMV is not proportional to the level of ventilatory support and patient is only supported on mandatory breaths [26]. This effect can be overcome by adding PSV to the unsupported breaths during SIMV [27].

Choosing ventilatory support — We suggest performing the SBT with some form of ventilatory support (eg, low-level PSV, automatic tube compensation [ATC] or continuous positive airway pressure [CPAP; eg, 5 cm H2O]) rather than no ventilatory support (eg, using a T-piece (figure 1)). Choosing among the options for ventilator support is often institution- or clinician-dependent. In our practice, we typically use PSV (eg, inspiratory pressure augmentation of 5 to 8 cm H2O), which is consistent with the recommendations of the American College of Chest Physicians/American Thoracic Society [28-30]. When using PSV-SBT, the positive end-expiratory pressure (PEEP) remains at 5 cm H2O and the fraction of inspired oxygen (FiO2) at 0.4 or lower.

Our approach is based on the rationale that PSV mitigates any increased work of breathing due to resistance of the ETT [26,27,31-34]. This is especially important for patients with small ETTs (eg, size ≤7 mm), but even larger ETTs can have considerable narrowing of the lumen after intubation [32]. In addition, using PSV, ATC, or CPAP during the SBT allows the ventilator's monitoring system and alarms to alert the clinician if there are changes in the patient’s respiratory rate, tidal volumes, or minute ventilation; whereas such monitoring is not possible if a T-piece is used (figure 1). The practice of performing the SBT on PSV is supported by several clinical trials (described below) that suggest PSV-SBT leads to higher rates of successful extubation compared with other methods [30].

Ventilatory support in the form of CPAP in patients at risk for acute cardiogenic pulmonary edema and patients with acute hypercapnia from obstructive lung disease may result in a falsely reassuring SBT, since CPAP is a form of therapy and reduces the work of breathing for both of these conditions, especially in COPD patients with intrinsic PEEP [35-38]. A T-piece may be more appropriate in such conditions particularly when patients fail an initial PSV-SBT. Ventilatory support with ATC is not used frequently and its use may be institution-dependent.

The evidence supporting the use of PSV-SBT comes from several randomized trials and a meta-analysis [28,30].

The largest trial included 1153 patients who were deemed ready for weaning and were then randomized to a 30-minute trial on PSV (8 cm H2O) or a two-hour T-piece trial [30]. More patients in the PSV-SBT arm achieved successful extubation at 72 hours compared with those in the T-piece arm (82 versus 74 percent). In addition, 90-day mortality was lower in the PSV-SBT group (13 versus 17 percent; hazard ratio 0.74, 95% CI 0.55-0.99). Reintubation rates and hospital length of stay were similar in both groups. The findings were consistent across various subgroups, including older patients (>70 years), those ventilated for longer than four days, medical and surgical patients, and those with COPD. However, more patients in the PSV-SBT group received some form of noninvasive support (ie, high flow oxygen delivered via nasal cannulae [HFNC] or NIV) following extubation (25 versus 19 percent), which may have contributed to the higher extubation success rate in that group.

In an earlier meta-analysis of four randomized trials (875 patients), not including the trial described above, PSV-SBT compared with T-piece resulted in a higher rate of successful extubation (74 versus 67 percent) [28]. The effect on ICU mortality was not statistically significant (9 versus 12 percent; relative risk 0.74, 95% CI 0.45-1.24); however, only two trials reported this outcome and the meta-analysis may have been underpowered to detect a difference.

Data suggest superiority of PSV as compared with T-piece in patients at high risk of extubation failure:

In a post-hoc analysis of a clinical trial, among the 500 patients considered to be at risk of extubation failure (eg, underlying cardiorespiratory disease), the proportion of successful extubations was higher in patients who underwent a PSV trial compared with T-tube trial (67 versus 56 percent) [39]. Reintubation rates were similar (13 versus 10 percent).

In another trial (by the same group) of PSV 8 cm H2O without PEEP compared with T-piece among 969 patients considered at high risk of extubation failure (>65 years and/or had an underlying chronic cardiac or respiratory disease), there was no difference in the number of ventilator-free days (27 each) and reintubation rates (15 versus 14 percent) [40]. However, there was a modest increase in the proportion of successful initial SBTs in the PSV group (79 versus 72 percent), patients extubated within 24 hours (77 versus 72 percent), and patients extubated within seven days of the first SBT (98 versus 94 percent). Most patients received prophylactic noninvasive support immediately following extubation, which may have prevented the development of extubation failure (eg, noninvasive ventilation or HFNC). In addition, the absence of PEEP in the PSV arm more closely approximates a T-piece trial than if PEEP were applied to PSV. Last, the reintubation rates quoted in this study are rather low for patients considered at high risk of extubation failure. All of these issues may have potentially minimized the difference between the groups. (See "Extubation management in the adult intensive care unit", section on 'Postextubation management'.)

Smaller trials comparing SBTs performed with T-piece versus other forms of ventilatory support, including CPAP [41] and ATC [42], did not detect significant differences in extubation success rates.

A single small trial compared ATC with CPAP during the SBT and found a higher rate of extubation success with ATC (82 versus 65 percent) [43]. Another trial comparing ATC with PSV, found similar extubation success rates and reintubation rates in both groups [44].

Trial duration — We typically perform SBTs for a duration of 30 minutes to two hours, which is the range used in most of the available clinical trials. However, the optimal duration for an SBT is uncertain and it may depend upon the underlying reason for intubation, the duration of MV prior to the weaning trial, performance on previous SBTs, and physician- or institution-specific practices.

Our general approach is as follows:

Duration of MV <24 hours – Some patients who are intubated for <24 hours generally do not require an SBT, although a 30-minute SBT is unlikely to be harmful (eg, following surgery or for airway protection).

Duration of MV 1 to <10 days – In most patients who have been mechanically ventilated for <10 days, an initial SBT of 30 minutes duration is generally sufficient to determine whether mechanical ventilation can be discontinued [30,45,46]. In a multicenter trial of 526 patients receiving mechanical ventilation (most were intubated for <10 days) randomly assigned to 30-minute or 120-minute T-piece SBTs, rates of weaning failure and reintubation were virtually identical in both groups [45].

Duration of MV ≥10 days – For patients who are mechanically ventilated for more prolonged periods (eg, ≥10 days), trials of 30 minutes may still be sufficient [30,47]. However, we prefer an individualized approach and in many cases extend trials for up to two hours in this population. For example, patients with chronic respiratory failure who have undergone an extended duration of mechanical ventilation may warrant a longer SBT to ensure that they are ready for extubation. In one study of 75 patients with chronic obstructive pulmonary disease who were mechanically ventilated for 15 or more days, the median time to SBT failure was 120 minutes [46].

Subsequent SBTs after failed initial SBT – For patients who fail their initial SBT, we generally extend subsequent trials for longer than 30 minutes, up to two hours [46,48]. (See 'Weaning failure' below and "Management of the difficult-to-wean adult patient in the intensive care unit", section on 'Resuming weaning trials'.)

Alternative methods — Older methods of weaning are infrequently used as an initial weaning strategy [6,49]. These include progressive decreases in the level of pressure support during pressure support ventilation (PSV-weaning) and progressive decreases in the number of ventilator-assisted breaths during intermittent mandatory ventilation (IMV-weaning) [7,14]. These methods have largely been supplanted by SBT since data support a shorter duration of MV with SBT weaning when compared with PSV/IMV weaning. These data are discussed above. (See 'Daily spontaneous breathing trials (SBTs)' above.)

Pressure support weaning — There are several protocols that have been used for PSV weaning. As an example, pressure support may be initially set between 12 and 18 cm H2O (to target a spontaneous respiratory rate ≤25 breaths per minute). PSV is then reduced, if possible, by 2 to 4 cm H2O at least twice a day until a pressure support of 5 to 8 cm H2O is reached for two hours or more (ie, typically over a 24 hour period). More rapid reductions in PSV weaning have also been described. PEEP of up to 4 or 5 cm H2O is usually applied.

As previously discussed, the available clinical trial data suggest that PSV weaning protocols are effective in reducing MV duration compared with usual care (ie, weaning at the discretion of the attending physician). However, the data are conflicting as to whether PSV weaning has similar efficacy, superior efficacy, or inferior efficacy compared with daily SBTs. (See 'Evidence supporting daily SBTs' above.)

Intermittent mandatory ventilation — Several protocols have been used for intermittent mandatory ventilation (IMV) weaning. As an example, the ventilator rate may be initially set at 8 to 12 breaths per minute. The IMV rates is then decreased usually by 2 to 4 breaths per minute, if possible, at least twice a day until four or five breaths per minute or less is reached for two hours or more.

As previously discussed, the available clinical trial data suggest that IMV weaning protocols are effective in reducing MV duration compared with usual care (ie, weaning at the discretion of the attending physician). However, the data suggest that IMV weaning is not superior to daily SBTs, and may in fact be inferior. (See 'Evidence supporting daily SBTs' above.)

Extubation to noninvasive ventilation — In patients deemed ready to wean, a strategy of extubation with immediate application of NIV has been proposed as an option for select patients who fail the initial SBT (eg, patients with COPD or chronic hypercapnic respiratory failure). Extubation to NIV can also be used as a tool in patients at high risk of extubation failure. These issues are described separately. (See "Management of the difficult-to-wean adult patient in the intensive care unit", section on 'Method of weaning trial' and "Extubation management in the adult intensive care unit", section on 'Noninvasive ventilation'.)

Variation in practice — Weaning practice varies significantly among clinicians, hospitals, regions, and countries. Our preferred weaning method is consistent with observed practice in most US ICUs as illustrated in a multicenter, international prospective observational study of 1868 patients who were mechanically ventilated for at least 24 hours and admitted to one of 142 intensive care units (ICUs) in six geographic regions (Canada, US, UK, Europe, India, Australia/New Zealand) [50]. Most ICUs had a university affiliation and were medical surgical ICUs or multidisciplinary ICUs. The results were as follows:

Written directives to screen for SBT readiness varied widely, ranging from 5 to 83 percent. Written directives for screening were present in more than half of participating ICUs in Canada, India, and the US (83 percent) while written directives for SBT conduct were lower, though present in 78 percent of US ICUs. Similarly, the frequency of screening (eg, never, once daily, twice daily) and personnel involved (eg, nursing, respiratory therapist, clinician) also varied among regions; daily screening was conducted in 83 percent of US ICUs. Readiness testing is discussed separately. (See "Weaning from mechanical ventilation: Readiness testing".)

Approximately 20 percent of patients died prior to a weaning attempt and 8 percent underwent a direct tracheostomy. Among the remaining patients, over two-thirds underwent an SBT while the remaining third were directly extubated without an SBT. ICUs in the US were associated with greater odds of using an SBT compared with ICUs in other regions. Most regions outside the US were using pressure support mode before an SBT or direct extubation, while most ICUs in the US were receiving volume- or pressure-controlled modes of ventilation.

Among those who underwent an SBT, almost half used low-level pressure support (PSV) with positive end expiratory pressure (PEEP), while one quarter used a T-piece, and 11 percent used continuous positive airway pressure (CPAP). PSV with PEEP was more commonly used in all regions except India and Europe, where T-piece trials were the most common method used.

ASSESSMENT OF WEANING SUCCESS OR FAILURE — Regardless of the weaning strategy used, the clinician must determine whether weaning was a success or failure so that a decision for extubation can be made.

Clinical assessment — During the weaning trial, clinicians should monitor vital signs and ventilator parameters such as the tidal volume and respiratory rate (ie, minute ventilation). In addition, patients should be assessed for respiratory distress and mental status changes, and if alert and responsive, asked about the presence of dyspnea and chest pain. Telemetry monitors should also be examined for ST changes that might prompt electrocardiography to look for cardiac ischemia. At the end of the spontaneous breathing trial (SBT), an arterial or venous blood gas (ABG, VBG) is not always necessary. However, blood gas analysis is prudent in those at risk of developing acute hypercapnia during weaning (eg, patients with chronic obstructive pulmonary disease [COPD], patients who underwent prolonged mechanical ventilation, patients with known or suspected neuromuscular weakness).

Importantly, clinicians should use their clinical judgement at the bedside to make a final conclusion regarding success or failure. Nonetheless, several objective criteria were used during weaning trials to indicate failure. The development of one or more of these criteria listed in the table (table 2) generally indicates weaning failure [7,14].

While fever can contribute to weaning failure by inducing tachycardia and respiratory distress, it is not necessarily a criterion per se for designating the trial as a failure.

Weaning success — When a patient successfully passes a weaning trial, they should be evaluated for safety of extubation. This requires an assessment of the volume of respiratory secretions as well as airway patency and protection (ie, has a sufficient cough and adequate level of consciousness). Extubation is reviewed in detail separately. (See "Extubation management in the adult intensive care unit".)

For patients who successfully pass an SBT on low-level pressure support ventilation (PSV; eg, 7 cm H2O), it is not necessary to "rest" the patient by resuming prior ventilatory settings prior to extubation. However, if the SBT is performed on T-piece (figure 1), there may be a role for "resting" prior to extubation [51].

Weaning failure — In general, patients who fail a weaning trial should be placed back on their previous ventilator settings. No further attempts at weaning are typically made for another 24 hours, although rare exceptions can be made. For example, it is reasonable to repeat the weaning trial sooner in patients who have sedation-related failure (ie, hypoventilation from excessive somnolence) if they are subsequently more alert after weaning sedation.

Causes of weaning failure should be sought and treated, if feasible, before resuming further weaning trials (table 3). Management of patients who fail their initial SBT is discussed in detail separately. (See "Management of the difficult-to-wean adult patient in the intensive care unit".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Weaning from mechanical ventilation".)

SUMMARY AND RECOMMENDATIONS

Liberation from mechanical ventilation is a three-step process, consisting of readiness testing, weaning, and extubation. Weaning is the process of decreasing the amount of support that the patient receives from the mechanical ventilator, so the patient assumes a greater proportion of the ventilatory effort. The purpose is to assess the probability that mechanical ventilation can be successfully discontinued. (See 'Introduction' above.)

Initial approach to weaning – Practice varies widely. The steps below represent our approach to initial weaning in patients who have been intubated for more than 24 hours and have been deemed as ready to wean:

We recommend protocolized weaning rather than no protocol (ie, physician judgment) (Grade 1B). For most patients, we suggest manual weaning protocols (ie, personnel-driven) rather than automated weaning systems (ie, computer-driven) (Grade 2C). We prefer manual protocols because they can be tailored to the patient, they are less costly, and because most of the available clinical trials used manual protocols. Automated systems are a reasonable alternative. (See 'Selecting manual or automated weaning' above.)

For most patients, we suggest weaning via once-daily spontaneous breathing trials (SBTs), rather than gradual pressure support ventilation (PSV) or intermittent mandatory ventilation (IMV) weaning (Grade 2C). While gradual PSV and IMV weaning have been used in the past, the available evidence suggests that they are likely not superior to SBT. (See 'Daily spontaneous breathing trials (SBTs)' above and 'Alternative methods' above.)

For most patients, we suggest that the SBT be performed with low-level PSV (eg, 5 to 8 cm H2O) rather than through a T-piece (Grade 2B). Automatic tube compensation (ATC) or continuous positive airway pressure (CPAP) are reasonable alternatives to low-level PSV. T-piece trials may be appropriate in select patients if there is concern that a PSV trial may provide a falsely reassuring assessment of readiness to extubate (eg, patients with acute cardiogenic pulmonary edema and patients with hypercapnia from obstructive lung disease). (See 'Choosing ventilatory support' above.)

An initial SBT of 30 minutes duration is generally sufficient to determine whether mechanical ventilation can be discontinued. Trials of up to 120 minutes are appropriate for patients who fail their initial SBT and those with prolonged mechanical ventilation duration (eg, ≥10 days). (See 'Trial duration' above.)

Assessment of weaning success or failure – Clinical impression determines whether a patient fails or tolerates weaning. (See 'Assessment of weaning success or failure' above.)

Criteria for failure – Objective criteria used during weaning trials are listed in the table (table 2); the development of one or more of these indicates weaning failure. (See 'Clinical assessment' above.)

Weaning success – Patients who tolerate the SBT should be evaluated for extubation. The approach to extubating patients in the intensive care unit (ICU) is discussed separately. (See 'Weaning success' above and "Extubation management in the adult intensive care unit".)

Weaning failure – Patients who fail the SBT should be returned to previous ventilator settings. The reason for failure should be sought and corrected before resuming further weaning trials (table 3). Subsequently, the patient should be assessed for readiness to wean with daily SBTs. The approach to managing such patients is discussed separately. (See 'Weaning failure' above and "Management of the difficult-to-wean adult patient in the intensive care unit".)

  1. Esteban A, Anzueto A, Frutos F, et al. Characteristics and outcomes in adult patients receiving mechanical ventilation: a 28-day international study. JAMA 2002; 287:345.
  2. Coplin WM, Pierson DJ, Cooley KD, et al. Implications of extubation delay in brain-injured patients meeting standard weaning criteria. Am J Respir Crit Care Med 2000; 161:1530.
  3. Unroe M, Kahn JM, Carson SS, et al. One-year trajectories of care and resource utilization for recipients of prolonged mechanical ventilation: a cohort study. Ann Intern Med 2010; 153:167.
  4. Epstein SK, Ciubotaru RL, Wong JB. Effect of failed extubation on the outcome of mechanical ventilation. Chest 1997; 112:186.
  5. Boles JM, Bion J, Connors A, et al. Weaning from mechanical ventilation. Eur Respir J 2007; 29:1033.
  6. Esteban A, Ferguson ND, Meade MO, et al. Evolution of mechanical ventilation in response to clinical research. Am J Respir Crit Care Med 2008; 177:170.
  7. Esteban A, Frutos F, Tobin MJ, et al. A comparison of four methods of weaning patients from mechanical ventilation. Spanish Lung Failure Collaborative Group. N Engl J Med 1995; 332:345.
  8. Ely EW, Baker AM, Dunagan DP, et al. Effect on the duration of mechanical ventilation of identifying patients capable of breathing spontaneously. N Engl J Med 1996; 335:1864.
  9. Kollef MH, Shapiro SD, Silver P, et al. A randomized, controlled trial of protocol-directed versus physician-directed weaning from mechanical ventilation. Crit Care Med 1997; 25:567.
  10. Burns KE, Meade MO, Lessard MR, et al. Wean earlier and automatically with new technology (the WEAN study). A multicenter, pilot randomized controlled trial. Am J Respir Crit Care Med 2013; 187:1203.
  11. Girard TD, Alhazzani W, Kress JP, et al. An Official American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline: Liberation from Mechanical Ventilation in Critically Ill Adults. Rehabilitation Protocols, Ventilator Liberation Protocols, and Cuff Leak Tests. Am J Respir Crit Care Med 2017; 195:120.
  12. Blackwood B, Burns KE, Cardwell CR, O'Halloran P. Protocolized versus non-protocolized weaning for reducing the duration of mechanical ventilation in critically ill adult patients. Cochrane Database Syst Rev 2014; :CD006904.
  13. Ely EW, Bennett PA, Bowton DL, et al. Large scale implementation of a respiratory therapist-driven protocol for ventilator weaning. Am J Respir Crit Care Med 1999; 159:439.
  14. Brochard L, Rauss A, Benito S, et al. Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation. Am J Respir Crit Care Med 1994; 150:896.
  15. Dries DJ, McGonigal MD, Malian MS, et al. Protocol-driven ventilator weaning reduces use of mechanical ventilation, rate of early reintubation, and ventilator-associated pneumonia. J Trauma 2004; 56:943.
  16. Jordan J, Rose L, Dainty KN, et al. Factors that impact on the use of mechanical ventilation weaning protocols in critically ill adults and children: a qualitative evidence-synthesis. Cochrane Database Syst Rev 2016; 10:CD011812.
  17. Vitacca M, Clini E, Porta R, Ambrosino N. Preliminary results on nursing workload in a dedicated weaning center. Intensive Care Med 2000; 26:796.
  18. Miller MA, Krein SL, George CT, et al. Diverse attitudes to and understandings of spontaneous awakening trials: results from a statewide quality improvement collaborative*. Crit Care Med 2013; 41:1976.
  19. Burns KE, Lellouche F, Lessard MR, Friedrich JO. Automated weaning and spontaneous breathing trial systems versus non-automated weaning strategies for discontinuation time in invasively ventilated postoperative adults. Cochrane Database Syst Rev 2014; :CD008639.
  20. Rose L, Presneill JJ, Johnston L, Cade JF. A randomised, controlled trial of conventional versus automated weaning from mechanical ventilation using SmartCare/PS. Intensive Care Med 2008; 34:1788.
  21. Schädler D, Engel C, Elke G, et al. Automatic control of pressure support for ventilator weaning in surgical intensive care patients. Am J Respir Crit Care Med 2012; 185:637.
  22. Rose L, Schultz MJ, Cardwell CR, et al. Automated versus non-automated weaning for reducing the duration of mechanical ventilation for critically ill adults and children. Cochrane Database Syst Rev 2014; :CD009235.
  23. Burns KE, Lellouche F, Nisenbaum R, et al. Automated weaning and SBT systems versus non-automated weaning strategies for weaning time in invasively ventilated critically ill adults. Cochrane Database Syst Rev 2014; :CD008638.
  24. Perkins GD, Mistry D, Gates S, et al. Effect of Protocolized Weaning With Early Extubation to Noninvasive Ventilation vs Invasive Weaning on Time to Liberation From Mechanical Ventilation Among Patients With Respiratory Failure: The Breathe Randomized Clinical Trial. JAMA 2018; 320:1881.
  25. Laghi F, D'Alfonso N, Tobin MJ. Pattern of recovery from diaphragmatic fatigue over 24 hours. J Appl Physiol (1985) 1995; 79:539.
  26. Imsand C, Feihl F, Perret C, Fitting JW. Regulation of inspiratory neuromuscular output during synchronized intermittent mechanical ventilation. Anesthesiology 1994; 80:13.
  27. Jounieaux V, Duran A, Levi-Valensi P. Synchronized intermittent mandatory ventilation with and without pressure support ventilation in weaning patients with COPD from mechanical ventilation. Chest 1994; 105:1204.
  28. Ouellette DR, Patel S, Girard TD, et al. Liberation From Mechanical Ventilation in Critically Ill Adults: An Official American College of Chest Physicians/American Thoracic Society Clinical Practice Guideline: Inspiratory Pressure Augmentation During Spontaneous Breathing Trials, Protocols Minimizing Sedation, and Noninvasive Ventilation Immediately After Extubation. Chest 2017; 151:166.
  29. Schmidt GA, Girard TD, Kress JP, et al. Official Executive Summary of an American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline: Liberation from Mechanical Ventilation in Critically Ill Adults. Am J Respir Crit Care Med 2017; 195:115.
  30. Subirà C, Hernández G, Vázquez A, et al. Effect of Pressure Support vs T-Piece Ventilation Strategies During Spontaneous Breathing Trials on Successful Extubation Among Patients Receiving Mechanical Ventilation: A Randomized Clinical Trial. JAMA 2019; 321:2175.
  31. Ezingeard E, Diconne E, Guyomarc'h S, et al. Weaning from mechanical ventilation with pressure support in patients failing a T-tube trial of spontaneous breathing. Intensive Care Med 2006; 32:165.
  32. Wilson AM, Gray DM, Thomas JG. Increases in endotracheal tube resistance are unpredictable relative to duration of intubation. Chest 2009; 136:1006.
  33. DeHaven CB, Kirton OC, Morgan JP, et al. Breathing measurement reduces false-negative classification of tachypneic preextubation trial failures. Crit Care Med 1996; 24:976.
  34. Kirton OC, DeHaven CB, Morgan JP, et al. Elevated imposed work of breathing masquerading as ventilator weaning intolerance. Chest 1995; 108:1021.
  35. Naughton MT, Rahman MA, Hara K, et al. Effect of continuous positive airway pressure on intrathoracic and left ventricular transmural pressures in patients with congestive heart failure. Circulation 1995; 91:1725.
  36. Bradley TD, Holloway RM, McLaughlin PR, et al. Cardiac output response to continuous positive airway pressure in congestive heart failure. Am Rev Respir Dis 1992; 145:377.
  37. Tobin MJ. Extubation and the myth of "minimal ventilator settings". Am J Respir Crit Care Med 2012; 185:349.
  38. Reissmann HK, Ranieri VM, Goldberg P, Gottfried SB. Continuous positive airway pressure facilitates spontaneous breathing in weaning chronic obstructive pulmonary disease patients by improving breathing pattern and gas exchange. Intensive Care Med 2000; 26:1764.
  39. Thille AW, Coudroy R, Nay MA, et al. Pressure-Support Ventilation vs T-Piece During Spontaneous Breathing Trials Before Extubation Among Patients at High Risk of Extubation Failure: A Post-Hoc Analysis of a Clinical Trial. Chest 2020; 158:1446.
  40. Thille AW, Gacouin A, Coudroy R, et al. Spontaneous-Breathing Trials with Pressure-Support Ventilation or a T-Piece. N Engl J Med 2022; 387:1843.
  41. Jones DP, Byrne P, Morgan C, et al. Positive end-expiratory pressure vs T-piece. Extubation after mechanical ventilation. Chest 1991; 100:1655.
  42. Haberthür C, Mols G, Elsasser S, et al. Extubation after breathing trials with automatic tube compensation, T-tube, or pressure support ventilation. Acta Anaesthesiol Scand 2002; 46:973.
  43. Cohen JD, Shapiro M, Grozovski E, et al. Extubation outcome following a spontaneous breathing trial with automatic tube compensation versus continuous positive airway pressure. Crit Care Med 2006; 34:682.
  44. Cohen J, Shapiro M, Grozovski E, et al. Prediction of extubation outcome: a randomised, controlled trial with automatic tube compensation vs. pressure support ventilation. Crit Care 2009; 13:R21.
  45. Esteban A, Alía I, Tobin MJ, et al. Effect of spontaneous breathing trial duration on outcome of attempts to discontinue mechanical ventilation. Spanish Lung Failure Collaborative Group. Am J Respir Crit Care Med 1999; 159:512.
  46. Vitacca M, Vianello A, Colombo D, et al. Comparison of two methods for weaning patients with chronic obstructive pulmonary disease requiring mechanical ventilation for more than 15 days. Am J Respir Crit Care Med 2001; 164:225.
  47. Liang G, Liu T, Zeng Y, et al. Characteristics of Subjects Who Failed a 120-Minute Spontaneous Breathing Trial. Respir Care 2018; 63:388.
  48. Teixeira C, da Silva NB, Savi A, et al. Central venous saturation is a predictor of reintubation in difficult-to-wean patients. Crit Care Med 2010; 38:491.
  49. Burns KEA, Raptis S, Nisenbaum R, et al. International Practice Variation in Weaning Critically Ill Adults from Invasive Mechanical Ventilation. Ann Am Thorac Soc 2018; 15:494.
  50. Burns KEA, Rizvi L, Cook DJ, et al. Ventilator Weaning and Discontinuation Practices for Critically Ill Patients. JAMA 2021; 325:1173.
  51. Fernandez MM, González-Castro A, Magret M, et al. Reconnection to mechanical ventilation for 1 h after a successful spontaneous breathing trial reduces reintubation in critically ill patients: a multicenter randomized controlled trial. Intensive Care Med 2017; 43:1660.
Topic 1650 Version 39.0

References

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